From my own experience and seeing multiple builds in competition, below is a list of common materials used.
- Aluminum bars or plates
- Lexan sheet (plastic, also used for the arena walls)
- Titanium bars or plates
- Steel bars or plates (less common, as it is heavy)
- UHMW (ultra high molecular weight polyethylene) (tough plastic similar to a kitchen cutting board)
- 3D printed materials (PLA, ABS, PETG, Nylon, Carbon Fiber)
How to choose? Every bot I have seen usually uses a combination of materials for armor, depending on your design and placement. (Protecting the wheels, top/bottom plates for the internal electronics and motors, etc.) As with most materials, each have their own pro’s and con’s. Some are heavier but stronger, some are more flexible but can tear or bend. Choose your materials based on your design, test it, and change as needed.
Note: 3D printing has become extremely popular in recent years. Before you get into 3D printing a bot, make sure understand how it works and the limitations of the materials themselves (filament type). Choosing the wrong filament can mean the difference between a tough bot and one that shatters like glass on impact!